Tetragonal /(?)/

Te·trag·o·nal

Tetragonal

a.
  1. Of or pertaining to a tetragon; having four angles or sides; thus, the square, the parallelogram, the rhombus, and the trapezium are tetragonal fingers. (Geom.)
  2. Having four prominent longitudinal angles. (Bot.)
  3. Designating, or belonging to, a certain system of crystallization; dimetric. See Tetragonal system, under Crystallization. (Crystallog.)